[en]This paper deals with the enforcement of merger policy, and aims to identify situations where the introduction of remedies can lead to a lower welfare. For this we study how merger remedies affect the deterrence accomplished by controlling mergers, and determine the optimal frequency of investigations launched by the agency. We find that when conditional approvals are possible, it may be harder to deter the most welfare-detrimental mergers, and the agency might have to investigate mergers more often. The resulting welfare from merger control can indeed be lower than without remedies.[/en]